The present application relates generally to a control system and method for a harvester spout. The present application relates more specifically to a control system and method to control the operation or position of the harvester spout during “unload on the go” operation of the harvester.
Harvesters or harvesting machines pick up crop material, treat the crop material, e.g., remove any undesirable portions or residue, and discharge the crop material. Harvesters can discharge the crop material, either continuously as with a forage harvester or after intermediate storage as with a combine harvester, to a transport or transfer vehicle. The transport vehicle may be a tractor or truck pulling a cart, wagon, or trailer, or a truck or other vehicle capable of transporting harvested crop material. The harvested crop material is loaded into the transport vehicle via a crop discharging or unloading device, such as a spout or discharge auger, associated with the harvester.
During “unload on the go” operation of the harvester, the harvested crop material is transferred from the harvester to the transport vehicle while both vehicles are moving. The transport vehicle can travel next to and/or behind the harvester during unload on the go operation. Unload on the go operation is required for a forage harvester, since the forage harvester constantly discharges the harvested crop material. While unload on the go operation is not required for a combine harvester due to the combine harvester's intermediate storage capability, unload on the go operation is commonly used for a combine harvester to maximize the operating efficiency of the combine harvester.
To effectively implement unload on the go operation, the operation of the harvester and transport vehicle is coordinated to maintain the relative distance between the harvester and transport vehicle within an acceptable range. By maintaining the relative distance of the harvester and transport vehicle within an acceptable range, the position and orientation of the harvester unload spout and the position of the transport vehicle, specifically the portion of the transport vehicle receiving crop material, relative to the harvester unload spout position are maintained within an acceptable distance range to permit harvester unload on the go operation, i.e., the discharged crop material can be provided into the transport vehicle without loss to the ground. That is, discharged crop material is directed to collect in the transport vehicle and is substantially prevented from being misdirected to miss the transport vehicle and collecting on the ground resulting in waste or loss of crop material. In order to maintain an acceptable distance range between the harvester and the transport vehicle, both the lateral (side to side) distance and longitudinal (fore and aft) distance between the harvester and transport vehicle have to be maintained within acceptable ranges.
Using a global positioning system (GPS) based auto-guidance system, auto-steering of the harvester and transport vehicle can maintain a lateral distance between the harvester and transport vehicle within an acceptable range. With a wireless communication link between the harvester and transport vehicle, each machine can communicate its corresponding position provided by the GPS system to the other machine. A master machine, such as a harvester, operates in a way to best perform the harvesting operation, while the slave machine, such as a transport vehicle, follows the GPS auto-guidance system's steering function to maintain an acceptable lateral distance from the master machine. Similarly, using a GPS based longitudinal distance control system, the longitudinal distance of the two machines can be controlled to be within an acceptable range during normal unload on the go operation.
However, the GPS based auto-guidance system may not be able to maintain an acceptable distance range between the harvester and the transport vehicle in the event of an unexpected field condition that results in a sudden speed change or position change of one or both of the harvester and transport vehicle. In other words, position synchronization between the harvester and transport vehicle can be broken by unexpected field conditions because the speed adjustment or position adjustment by the auto-guidance system may not occur quickly enough in order to prevent harvested crop material from dropping onto the ground. Some examples of unexpected field conditions that may occur during an unload on the go operation include obstacles, unexpected animals, stones, a furrow or washed out spot, a circle irrigation wheel rut, etc.
Therefore, what is needed is a system and method to prevent crop material loss to the ground caused by sudden vehicle speed changes or position changes during unload on the go operation.